Interactive AC modeling and characterization of analog circuits via symbolic analysis

Optimal Design of a CMOS OpAmp via Geometric Programming

“…For the op-amp considered here, the analytical expressions for the constraints and specifications were derived by hand, but in a more general setting this step could be automated by the use of symbolic circuit simulators like ISAAC [36], SYNAP [83] and ASAP [32]. A CAD tool for optimization of analog op-amps could be developed.…”

Computer-aided design of analog and mixed-signal integrated circuits

“…Therefore, since the late 1980s, and in principle similar to what designers do during hand calculations, dedicated symbolic analysis tools have been developed that use heuristic simplification and pruning algorithms based on the relative importance of the different circuit elements to reduce the complexity of the resulting expressions and retain only the dominant contributions within user-controlled error tolerances. Examples of such tools are ISAAC [51], SYNAP [53], and ASAP [54] among many others. Although successful for relatively small circuits, the fast increase of the CPU time with the circuit size restricted their applicability to circuits between 10 and 15 transistors only, which was too small for many practical applications.…”

Global design of analog cells using statistical optimization techniques

“…On the other hand, in regions where some weak specifications are violated, temperature is given as, (12) where k max is the weight associated to the maximum among the F w (•)'s in (6), and T o is the normalized temperature at the current iteration. Finally, if both strong and weak restrictions hold, temperature is given as, (13) where w i is the weight associated to the i-th design objective.…”

“…The distinctive feature is that some of the design equations for new topologies are automatically generated via auxiliary symbolic analysis tools [9], [12].…”